Rory O'Sullivan

Factors associated with internal hip rotation gait in patients with cerebral palsy

Abstract: Internal rotation gait is common in children with cerebral palsy. Factors thought to contribute include femoral anteversion, hip flexor tightness, imbalance of hip rotators, and hamstring and adductor tightness. The exact cause of internal rotation must be defined before contemplating surgery. We investigated the prevalence of internal hip rotation and associated factors, which are considered to influence this walking pattern, in patients with cerebral palsy. Gait laboratory data of 222 patients with cerebral palsy were studied retrospectively. Two groups were selected; those with maximum dynamic hip internal rotation of more than 27 degrees and those with less than 20 degrees. Of 222 patients, 27.0% (diplegia, 61.7%; hemiplegia, 38.3%) had at least one hip with dynamic internal rotation of more than 27 degrees. This study suggests that dynamic hip internal rotation is multifactorial in origin. The most significant differences in clinical measures were found in values of passive hip external rotation range, femoral anteversion and hip flexor contracture. We discuss the role of early treatment of hip flexion contracture.

The influence of estimated body segment parameters on predicted joint kinetics during diplegic cerebral palsy gait

Inverse Dynamic calculations are routinely used in joint moment and power estimates during gait with anthropometric data often taken from published sources. Many biomechanical analyses have highlighted the need to obtain subject-specific anthropometric data (e.g. Mass, Centre of Mass, Moments of Inertia) yet the types of imaging techniques required to achieve this are not always available in the clinical setting. Differences in anthropometric sets have been shown to affect the reactive force and moment calculations in normal subjects but the effect on a paediatric diplegic cerebral palsy group has not been investigated. The aim of this study was to investigate the effect of using different anthropometric sets on predicted sagittal plane moments during normal and diplegic cerebral palsy gait. Three published anthropometric sets were applied to the reactive force and moment calculations of 14 Cerebral Palsy and 14 Control subjects. Statistically significant differences were found when comparing the different anthropometric sets but variability in the resulting sagittal plane moment calculations between sets was low (0.01-0.07 Nm/kg). In addition, the GDI-Kinetic, used as an outcome variable to assess whether differences were clinically meaningful, indicated no clinically meaningful difference between sets. The results suggest that the effects of using different anthropometric sets on the kinetic profiles of normal and diplegic cerebral palsy subjects are clinically insignificant.

Use of a dynamic foot pressure index to monitor the effects of treatment for equinus gait in children with cerebral palsy.

The purpose of this study is to introduce and describe a newly developed index using foot pressure analysis to quantify the degree of equinus gait in children with cerebral palsy before and after injection with botulinum toxin. Data were captured preinjection and 12 weeks postinjection. Ten children aged 2½ to 6½ years took part (5 boys and 5 girls). Three of them had a diagnosis of spastic diplegia and 7 of congenital hemiplegia. In total, 13 limbs were analyzed. After orientation and segmentation of raw pedobarographic data, we determined a dynamic foot pressure index graded 0 to 100 that quantified the relative degree of heel and forefoot contact during stance. These data were correlated (Pearson correlation) with clinical measurements of dorsiflexion at the ankle (on a slow and fast stretch) and video observation (using the Observational Gait Scale). Pedobarograph data were strongly correlated with both the Observational Gait Scale scores (R2 = 0.79, P < 0.005) and clinical measurements of dorsiflexion on a fast stretch, which is reflective of spasticity (R2 = 0.70, P < 0.005). We demonstrated the indexs sensitivity in detecting changes in spasticity and good correlation with video observations seems to indicate this techniques potential validity. When manipulated and segmented appropriately, and with the development of a simple ordinal index, we found that foot pressure data provided a useful tool in tracking changes in patients with spastic equinus.

The knee kinematic pattern associated with disruption of the knee extensor mechanism in ambulant patients with diplegic cerebral palsy.

Failure of the knee extensor mechanism is a potentially disastrous complication of diplegic cerebral palsy and if left undiagnosed may lead to a cessation of independent walking. The disruption of the extensor mechanism usually occurs through or distal to the patella. The aim of this article is to describe the knee kinematic pattern associated with such knee pathology. We also present a mathematical model of knee crouch that leads to this problem. In a retrospective review of patients with radiographically proven disruption, we compared the postfailure clinical and kinematic data to premorbid data. All patients included in this study had attended our clinical Gait Analysis Laboratory on two occasions. In the patients with disruption of the extensor mechanism, the kinematic pattern changed from crouch with shock absorption to one of increased crouch and loss of shock absorption. Clinical characteristics included knee flexion contracture and increased hamstring tightness. We demonstrate how the prefailure crouch position of the knee increases the flexor moment arm about the knee. We suggest that this knee crouch position during walking is the primary cause of pathology. Failure of the knee extensor mechanism is associated with a distinctive knee kinematic pattern. Regular gait analysis can help identify this pathology and enable treatment to be planned accordingly. Clin. Anat. 23:586–592, 2010.

Knee extensor disruption in mild diplegic cerebral palsy: a risk for adolescent athletes

We report three cases of adolescent boys with mild diplegic cerebral palsy (CP) who suffered disruption of the knee extensor mechanism. Two had fractures of the patella and the third a fracture avulsion of the tibial tubercle combined with an undisplaced fracture of the patella. All three had gait analysis prior to sustaining the fractures and were known to have mild knee crouch. Each participated in sport including football. Each suffered an acute deterioration in gait resulting in a referral for repeat gait analysis, and x-ray of the affected knee. With the increased involvement of children with CP in sporting activities, especially children with mild knee crouch, we caution that knee extensor rupture might be an increasing problem.

Run kinematics with and without a jogging stroller

BACKGROUND Jogging strollers have become increasingly popular as they allow a parent the freedom to run without having to leave their children. Few studies have examined the effects of running with a stroller and no study to date has examined the effects on joint kinematics. The aim of this study was to compare lower limb and trunk kinematics while running with and without a jogging stroller. METHODS Participants (N=15) ran on a 16-metre indoor runway, with and without a stroller, at their self-selected comfortable training speed. Three-dimensional trunk and lower limb kinematics were assessed using the CODA cx1 active marker system. FINDINGS The jogging stroller led to reduced movement of the trunk in both the transverse [mean difference -11.4°, 95% confidence interval (CI) (-14.8°, -8.2°), p<0.001] and coronal [-2.9°, 95% CI (-0.8°, -4.9°), p=0.009] planes most likely due to fixing of the upper limbs. There was also a 6.7° [95% CI (-9°, -4.6°), p<0.001] increase in forward trunk lean, 2.8° [95% CI (-4.2°, -1.7°), p<0.001] increase in anterior pelvic tilt and a 3° [95% CI (-4.4°, -1.5°), p=0.001] decrease in hip extension. There were no significant changes in knee or ankle kinematics and no changes in stride length, cadence or stance time. INTERPRETATION Our data suggest that jogging strollers lead to minor changes in trunk, pelvis and hip kinematics with no significant changes at the knee and ankle. Due to the changes in kinematics we suggest that flexibility work for the spine, pelvis and hips may be recommended.